Rheological Analysis of Polysaccharide Hydrogels

This research highlights the viscoelastic responses of high amylose (Amy) starch-epichlorohydrin (ECH) hydrogels. Besides establishing the correlation between the amounts of reaction components and properties of the networks, the influence of the Amy ratio and incorporation of hyaluronic acid (HA) are also evaluated. The resulting materials are examined by their swelling, viscoelastic, and also morphological properties. While elastic and viscous moduli are an increasing function of starch and ECH feed amounts, the mol ratio of NaOH is found to be a key parameter in the crosslinking reactions. During the continuous step-strain test, the network with low Amy ratio loses approximate to 92 +/- 4% of its initial mechanical strength, high amylose gels with and without HA are completely returned to the original states after sol-gel transitions. Time dependent relaxation moduli are observed for high Amy gels and the dynamics are slightly suppressed by the incorporation of HA with smaller and more stable pore structures.